Basketballs have been standardized into an eight-panel outer surface design having raised seams exposed between the edges of exterior skin panels. Basketballs generally consist of a rubber bladder surrounded by a thread-winding layer.
The arrangement of the bladder, thread-winding portion, and a rubber layer are placed in a mold and cured to make the “carcass” of the ball.
During the carcass molding process, raised ridges or seams are molded from the rubber layer. An individual panel section of leather is bonded to the rubber layer in a region between raised seams. After attachment of the panels the ball is completed in a finishing mold.
Basketballs have been made in the above manner. The thread-winding layer around the surface limits expansion of the bladder and assists it in retaining a spherical shape after inflation to a desired pressure. It also prevents the air pressure within the bladder from being fully transferred to the outer covering defined by the panel portions and seams.
The outer covering provides durability and protection. It is common to use synthetic materials to make the panel portions. However, the highest quality balls use top-grain leather.
One ball design developed in the past by the A. G. Spalding Co. (“Spalding design”) includes a porous sponge layer positioned between what is characterized as an “inner carcass” and an outer skin. This design is illustrated in U.S. Pat. No. 3,119,618.
The Spading design lacks the rubber layer described above for creating raised seams on the ball described in U.S. Pat. No. 3,119,618.
On the one hand, the invention disclosed in U.S. Pat. No. 5,636,835 is an inflatable, raised scam game ball having a layer of padding underneath the outer covering.
The carcass of the ball is preferably made in the following manner.
Surrounding a spherical rubber bladder by a thread-winding layer;
After the thread-winding layer is wound around the bladder, providing a layer of foamable rubber in a prefoamed condition around the thread-winding layer and covering it completely;
Applying a foaming agent to the foamable rubber;
Positioning narrow strips of seam material (high density black rubber) over the foamable rubber at the locations where it is desired to create raised seams;
Placing this arrangement in a carcass mold where it is cured under temperature in a conventional method;
During the molding process, expanding the foamable layer into a porous sponge rubber layer. At the same time, the seam strips are molded into raised seams;
As a result, when removed from the mold, raised black seams form partially covering the surface of the sponge layer and the sponge rubber layer covering the thread-winding layer.
As with typical leather game balls, the boundaries of the exterior skin panels are defined by the raised seams. Each panel is bonded in a region between seams.
A basketball illustrated in U.S. Pat. No. 5,636,835 has an inner carcass structure, or inner carcass portion, consisting, in combination, of a rubber bladder 12 and a thread-winding layer 14 (see, for example, FIG. 1).
The thread-winding layer 14 surrounds the bladder 12, and the porous sponge 16 surrounds the thread-winding layer 14. A plurality of skin panels 18 and a plurality of seams 20 are bonded to the porous layer 16. Generally, the ball 10 has a total of eight panels separated by seams, which is typical of basketballs.
Each seam 20 is made of a narrow strip of seam material preferably of a high density rubber. A raised central portion 22 of the seam material 20 fills the space between the outer edges 24 and 26 of two adjacent skin panels 28, 30 as well as conventional basketballs.
However, narrow flanges portions 32, 34 of the seam material 20 extend outwardly, in opposite directions, a definite distance from the raised portion 22 which is different from conventional basketballs.
The flange portions 32, 34 underlie the overlapping panel edges 24, 26 and are also sandwiched between the panel edges and underlying sponge layer 16. In other areas, the skin panels 18a, 18b are bonded directly to the sponge layer 16, as shown by numerals 36, 38. A basketball illustrated in U.S. Pat. No. 3,119,618 has no rubber layer for making a raised seam. However, instead of providing a raised seam, it is well known to provide a protrusion in a sponge layer (for example, Japanese Unexamined Utility Model Publication No. 157253/1976).
Referring to FIGS. 2 and 3, a basketball as illustrated in Japanese Unexamined Utility Model Publication No. 157253/1976 includes a bladder 51 made of butyl rubber, thread-winding layer of nylon thread 52 wound uniformly around the outside of the bladder 51, and vulcanized rubber 53 covering the outside of thread-winding layer 52. The vulcanized rubber 53 includes bubbles, and provides a very soft touch.
The carcass 54 is constructed by the bladder 51, thread-winding layer 52, and vulcanized rubber layer 53. Numeral 55 indicates a partition formed on the carcass 54. The surface of carcass 54 is sectionalized into the shape of a carapace of a turtle with 8 sections, 12 sections, 18 sections, or 32 sections. Numeral 56 indicates a surface sectionalizing and dividing on the surface surrounded by the partition 55. Numeral 57 indicates a spherical surface of the surface 56 in the shape of a sphere sectionalizing and dividing on the surface. Numeral 58 indicates a peripheral portion of surface 56 which is divided to sectionalize the surface with the shape of arc on its cross section. The peripheral portion 58 smoothly bonds to the spherical surface 57. Numeral 59 is a side of a partition, making an acute angle with the peripheral portion 58 described above. Numeral 60 is leather which is attached to the surface 56 which is divided to sectionalize the surface, and thin as compared to conventional leather. The periphery of a back surface of leather 60 is not skived. The cross section of attached leather 60 is directly bonded to the center of side 59 of the partition 55. Thus, when using ball, the cross sectional surface of the attached leather 60 is not peeled from the peripheral edge of leather 60 by catching fingers on the surface of the ball. As leather 60 is thin, it is readily attached. As the peripheral edge portion 58 has a cross section with the shape of a circular arc and is bonded smoothly to the spherical surface 57, unevenness does not occur on the surface of the attached leather 60 and very good handling in use is provided.
A basketball illustrated in Japanese Unexamined Utility Model Publication No. 157253/1976 constructs the peripheral edge 58 of each surface 56 which is divided to sectionalize the surface in the shape of an arc with the smooth seam by a much smaller radius than a radius of the ball on an arbitrary virtual plane which penetrates into the center of the ball. The side face 59 of partition 55 is formed, so that a virtual straight line drawn on the side face 59 of partition 55 penetrates into approximately the center of the ball. The leather 60, which has a uniform thickness without skiving, is applied on the surface 56 which is divided to sectionalize the surface.